Method of flaring tubes



July 14, 1936. w BElKMANN 2,047,849 7 METHOD OF FLARING TUBES Filed May17, 1933 m y is.)

5 T U *1 co 9 E? L Eu 4 Inventor." W BlKMAhh Patented July 14, 1936UNITED STATES PATENT OFFICE Application May 17, 1933, Serial No. 671,580In Germany December 16, 1932 8 Claims. (01. 205-7) This inventionrelates to a method and device for flaring tubes by drawing.

Flaring of tubes by drawing was carried out hitherto by supporting thetube to be drawn relative to a traverse and then drawing a plug oflarger diameter through the tube from the free end thereof. This methodsufiers from the drawback that the tube during the drawing process issubjected to compressive strain in longitudinal l0 direction so as tocollapse easily. For this reason it is necessary to keep the strain lowor to do the flaring while the tube is cold, and this explains why it isimpossible to do any flaring worth mentioning.

It is the object of the invention to provide a method and means whichmake it possible to draw up tubes to a considerably greater extent bysubjecting the tube during the drawing process to tensile stress by asuitable arrangement of its abutment. It will then be possible to workthe tube while it is red hot and to carry out a relatively large amountof flaring in one operation. Furthermore, if devices according to theinvention are provided in order to draw several conical 5 plugs onebehind the other and in one operation through the tube, an opportunityis afiorded of attaining at one heating of the tube a degree of flaringthat could not be economically pro- .duced hitherto.

By way of example, the invention is illustrated in the accompanyingdrawing, in which Figure 1 is a longitudinal section of a tube withflange prepared for drawing; Fig. 2, a longitudinal section of a tubehaving a pilger head; Fig. 3, a longitudinal section of a drawing deviceaccording to the invention; Fig. 3a is a partial plan view according toFig. 3 showing-especially the driving mechanism of the drawing rod, andFig. 4, an.

end view of this device as seen from the side of the lifting table.

In order to carry out the method according to the invention a draw benchis provided with an abutment block carrying a draw plate (11, az dividedon the plane of the ans- The half member m of the draw plate is disposedin the lower fixed having previously been brought to drawing temperatureis rolled from the side into the drawing frame whose upper half isturned up so as to be adjacent with the flange f or the pilger head 11to the lower half of the draw plate a1, a2, whereupon the top half 0 ofthe frame is turned down together with the upper half az of the drawplate. The conical drawing plugs sr, sz with increasing outer diameterare ready and disposed on atable 5 before theabutment block. Theypossess a bore through which the drawing rod 2 is pushed, and after thelatter has been passed through these bores, the plugs s1, s: areconnected with the rod 2'- by the wedges 701, kr and drawn through thetube 10 drel bar 2 in the bores of the plugs s1, s2, between theabutment block b, c and the table if a roll e capable of being raisedand lowered is provided, the stroke of the roll e being arranged so asto clear the way for the passage of the plugs s1, sz. 25

I claim:

1. Device for flaring tubes, comprising a bed, an annular bearing havinga supporting flange on one side arranged on said bed and dividedtransversely to its axis, a rod displaceably ar- 30 ranged in the axisof the annular bearing, cylindrical plugs arranged on the rod andsecured by wedges, said plugs having conical surfaces, a tableadjustable as to height for supporting the plugs, and a drivingdevice'arranged on the side turned 5 away from the supporting flange ofthe annular bearing and engaging the end of the drawing rod.

2. Device for flaring'tubes, comprising a 'bed,

a block disposed on the bed and provided with a cylindrical bore, saidblock being on the radial 40 plane divided into' two parts and capableof swinging with one part about an axis parallel to the axis of thebore, two halves of a ring member having a flange on one side, each halfbeing disposed "the rod is attached so as to be displaceable in I itsaxis, a driving device engaging the carriage, 5 cylindrical plugs ofdifierent diameter provided with conical surfaces, said plugsbeingpushed upon said rod by means of bores one behind the other andsecured by wedges thereto, a table adjustable as to height supportingthe underside of 55 .2) p the plugs, and a roll adjustable as to heightfor supporting the rod.

outer diameter of which is so great as compared with the small wallthickness that it cannot be attained by the mere rolling process,characterized by thefact that the flnal measurement is effected "bydrawing a mandrel through the tube by flaring to the greater outerdiameter, the tubes being held on the side of the mandrel inlet;

4. Amethod according to claim 3, characterized by the fact that the tubeis flared on the side of the mandrel inlet andis provided on the outerpedge of this enlargement with a projection whereby the workpiece issecured to an abutment when flaring while the enlargement itself extendsinto the abutment.

5. A method according to claim 3 for producing socket pipes,characterized by the fact that the inlet end for the flaring tools. is.flared in the form of the socket head and bears therewith against theabutment.

6. A method according to claim 3, characterized by the fact that aplurality of drawing plugs with an increasing diameter are drawn throughthe tube without re-heating the latter.

7. A method of flaring tubes having one end enlarged and flangedconsisting in heating the 3. A method of making seamless tubes, thevmain portion of the tube, then clamping and holding only the enlargedand flanged end thereof so as to support the tube and prevent axialdisplacement thereof, then repeatedly drawing pressure applying membersof increasing diameter axially through the major portion of the tubefrom the enlarged end while the latter is in a heated state to graduallyand uniformly. increase thecross sectional area thereof.

8. A methodof making seamless tubes of the type possessing an outerdiameter so great as compared with the small wall thickness that itcannot be obtained by a mere rolling process consisting in enlarging andfianging one end of a tube when in a cold state, then heating the mainportion of the tube only, then clamping and holding the enlarged end ofthe tube only so as to support the same and prevent axial displacement20 thereof, and then repeatedly drawing pressure applying members ofincreasing diameter axially through the tube from the enlarged end whilethe latter is in a heated state to gradually and uniformly increase thecross sectional area thereof. 25

WILHELM

